CCR2216 Rebooting boot loop

Suddenly both of my CCR2216 routers are in a boot loop. They come up, get the login, then rebooting…

Mikrotik 7.18.1 (stable)
routeros-1 Login:
Rebooting…

I’ve removed the interfaces to make sure there wasn’t something external causing it, and it just reboots and reboots and reboots.

How can I fix this?

Netinstall.

Sure, I know how to recover from it, but I have two of these in my config for redundancy, and both started reboot loop within 4 hours of each other which completely defeats the point of redundancy.

How would you try to not have this happen again?

The question is vague and there are no valid clues,
I would never have used a version higher than 7.16.2 in production in devices that must necessarily have v7 because they are not supported by v6.

Given the distance and the same problem,
I could forcefully deduce that some configuration, applied on one and then copied to the other, crashed the system and ruined the filesystem,
or that they both had the same username and password, and “someone” did some work on them…